Nail



P. F. BUTTERFIELD. v

NAIL.

APPLICATION FILED FEB. 10, 1919 J 1 ,326, 9 1 0.: Patented J an. 6, 1920.

PERCY FREDERIGK 'BUTTERFIELD, 0F TORONTO, ONTARIO, CANADA.

3 NAIL.

Leec -to.

specification of Letters Patent.

Patented Jan. e. 19%

Application filed. February 10, 1919. Serial No. 275,974.

To aZZ whom it mag concern." Be it known that l, PERCY FREDERICK BUTTERFIELD, of the city of Toronto in the .county of York, in the Province of (lntario, Canada have invented certain new and useful improvements in Nails, of which'the following is the specification.

My invention relates to improvements in nails and the object of the invention is to produce a nail which when driven, cannot withdraw out of wood by a dircet longitudinal movement of the nail and will,

- of the nail during the pulling thereof and therefore, permanently hold, the parts connected by the nail, together and which can only be withdrawn by a turning movement In the drawlngs like characters of reference indicate corresponding parts in the various figures.

1 indicates a nail. 2, 3, 4 and 5 indicate spiral grooves extending longitudinally of the nail and arranged at a quarter turnapart- The grooves 2, 3, i and 5 are of a low pitch corresponding to the pitch of the rifiing of a rifle Ibarrel. The grooves 2, 3,

4 and 5 are V-shaped in form and are provided at one side of each groove with a rib 6 extending outwardly fromthe surface of the nail, such rib terminating in a sharp edge. As the nail is driven the spiral rib 6 engages the wood and produces a turning movement of'the nail as it is forced into the wood, the portion of the wood compressed by the rib being forced into the groove and thereby is driven, a complete key preventing the longitudinal movement of the nail.

of the nail at each side of the groove.

forming, when the nail ln Figs. 3 and 4, l'have shown an alternative form. In this form 7 indicates the nail. S, 9, 10 and ll indicate spiral grooves extending longitudinally of the nail and corresponding inform to the groove shown in Fig. 1. In this form, however, the groove is provlded with projecting ribs 12 and 13, which extend outwardly from the surface In both forms as indicated in Figs. 2 and i the inner face of the rib is formed by a continu ation of the inner face of the corresponding side of the groove. 4

From this description it will be seen that l have devised a very simple device whereby a nail is absolutely prevented from withdrawing from the wood or other substance.

intowhich it is driven by a direct longitudinal movement and, therefore, securely fasten together the 'parts designed to be secured by the nail so that they cannot loosen apart and yet will allow of an easy withdrawal of, the nail by the hammer of'the workman when the nail is given a spiral twist as it is withdrawn.

What I claim is my invention is.-

v 1. A nail having a spiral groove extending longitudinally of the nail and having a rib extending outwardly from the surface of the nail at each edge of the groove.

2. A nail having a spiral groove extending longitudinally thereof V-shaped in form and having a sharpened rib extending from an edge of the groove, the inner face of the rib forming a continuation of the corresponding face of the grpove.

3. A nail having a spiral groove extending longitudinally thereof V-shaped in form andhaving a sharpened rib extending from eaoh'edge of the groove, the inner face of each rib forming a. continuation of the corresponding face of'the groove.

PERCY FREDERICK BUTTERFIELD.

Witnesses:

M. EGAN, 

